Does chronic physical activity level modify the airway inflammatory response to an acute bout of exercise in the postprandial period?

Abstract

Recent studies have confirmed that a single high-fat meal (HFM) leads to increased airway inflammation. However, exercise is a natural anti-inflammatory and may modify postprandial airway inflammation. The postprandial airway inflammatory response is likely to be modified by chronic physical activity (PA) level. This study investigated whether chronic PA modifies the airway inflammatory response to an acute bout of exercise in the postprandial period in both insufficiently active and active subjects. Thirty-nine nonasthmatic subjects (20 active, 13 males/7 females) who exceeded PA guidelines (≥150 min moderate-vigorous PA/week) and 19 insufficiently active (6 males/13 females) underwent an incremental treadmill test to exhaustion to determine peak oxygen uptake. Subjects were then randomized to a condition (COND), either remaining sedentary (CON) or exercising (EX) post-HFM. Exercise was performed at the heart rate corresponding to 60% peak oxygen uptake on a treadmill for 1 h post-HFM (63% fat, 10 kcal/kg body weight). Blood lipids and exhaled nitric oxide (eNO: marker of airway inflammation) were measured at baseline and 2 h and 4 h post-HFM. Sputum differential cell counts were performed at baseline and 4 h post-HFM. The mean eNO response for all groups increased at 2 h post-HFM (∼6%) and returned to baseline by 4 h (p = 0.03). There was a time × COND interaction (p = 0.04), where EX had a greater eNO response at 4 h compared with CON. Sputum neutrophils increased at 4 h post-HFM (p < 0.05). These findings suggest that airway inflammation occurs after an HFM when exercise is performed in the postprandial period, regardless of habitual activity level.

Keywords: activité physique; energy balance; exercice physique; exercise; inflammation; physical activity; physiologie pulmonaire; pulmonary physiology; équilibre énergétique.

Figure 1

Schematic of the study.

Figure 2

Triglyceride response post-HFM in ACT CON (●), ACT EX (○), IN CON (▼), IN EX (Δ). Data are shown as absolute means±SD. Triglycerides increased significantly from baseline to 2 hours and 4 hours, with no differences by activity level (AL) or condition (CON). Data points are offset to more clearly display the data. *Significant at p<0.05.

Figure 3

The mean eNO response in ACT CON (●), ACT EX (○), IN CON (▼), IN EX (Δ). There was a significant increase as a main effect of time (*), where eNO increased from baseline to 2 hours and then started to return to baseline by 4 hours post-HFM. There was a higher eNO response over time by CON (˄). Data points are offset to more clearly display the data. *Significant at p<0.05.